JPS6028899B2 - Amorphous metal alloy with high crystallization temperature and high hardness - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides amorphous metal alloy compositions, particularly those containing a substantial amount of the element Ta.
, Nb and W, which exhibit both high crystallization temperatures and high hardness values.

Research has shown that it is possible to obtain solid amorphous metals for certain alloy compositions, and the term "amorphous" here means "solid amorphous". do.

Amorphous materials are generally characterized as amorphous or glass materials. That is, the material has virtually no long-range order. Generally, it is appropriate to use X-ray diffraction measurements to distinguish between amorphous and crystalline substances. Furthermore, transmission electron microscopy and electron diffraction can be used to distinguish between amorphous and crystalline states. In X-ray diffraction images of amorphous metals, the intensity changes gradually with the diffraction angle.

It is qualitatively similar to the diffraction pattern of such liquids and ordinary window glass. On the other hand, in crystalline metals, the intensity of the diffraction pattern changes rapidly with the diffraction angle. These amorphous metals are in a metastable state.

When heated to a sufficiently high temperature, it crystallizes with the generation of heat of crystallization, and the diffraction pattern changes from having a glassy or amorphous character to having a crystalline character. It is possible to create metals that are two-phase mixtures of amorphous and crystalline, the relative proportions of which can vary from fully crystalline to fully amorphous.

Amorphous metal, as used herein, refers to a metal that is primarily amorphous, ie, at least 50% amorphous, but may have a small portion of material present as intercalated crystals. For appropriate compositions, appropriate processing will yield the metal in an amorphous state.

One typical operation is to spread the molten alloy in contact with a solid metal substrate, such as copper or aluminum, so that the heat of the molten metal is rapidly lost to the substrate. When the alloy is expanded to a thickness of about 0.002 inches, cooling temperatures on the order of 1 pC/sec will be achieved.

For example, R. C. See Ruhr (Materials Science and Engineering, Vol. 1, pp. 313-319, 1967), which discusses the dependence of cooling rate on molten metal processing conditions. For alloys of appropriate composition and for sufficiently high cooling rates, such processing yields amorphous metals. Any method that provides a suitably high cooling rate can be used. Illustrative examples of operations that can be used to create amorphous metals include days. S. Chiyan and C. E. Rotating double lo-fu as described by Miller (Review of Scientific Instruments, pages 1237-1238, 197), R. Pound Jr. and R. Madeline (Transactions of the
Metal Society, AIME, 249th Lid, 2475
- There is a rotating cylinder method as written by King (page 2476, 196g). Amorphous alloys containing substantial amounts of one or more of the elements Fe, Ni, Co, V and C have been developed. S. Chan and C. E. Miller, U.S. Patent Application No. 318,146, filed Dec. 26, 1972.

Such alloys are extremely useful for a variety of applications. However, such alloys have a crystallization temperature of about 425° to 550qo and a PH of about 600 to 75°.
It is characterized by its hardness. According to the invention, about 65
Amorphous alloys are described that have high thermal stability with crystallization temperatures in the range of 0° to 975° and high hardness with values in the range of about 800 to 140 PH.

Alloys with the general compositions below have these properties. That is, it is a refractory metal-based glassy metal having a composition represented by the general formula RrNisTt or RrNis, which can be called a metal-metal system.

where R is at least one of the elements tantalum, niobium and tungsten, T is at least one of the elements titanium and zirconium, and r is in the range of 35 to 65 atomic %, and s is 25 to 65 t is in the range of atomic percent, and t is in the range of atomic percent or less. The preferred composition represented by RrNis in the formula is Ta$NjsW65-s to Ta45NiS
W55-s (where s is about 35 to 45 at. %) and the composition Tarnis (where r is about 3
5 to 50 atom %, and s is about 0 to 65 atom %). The crystallization temperature of the metal-metal composition ranges from about 650° to 80,000° and the hardness ranges from about 800 to 112 PH. This type of metallic glass can be used at high temperatures (approximately 500o~600o
It is particularly useful for heat-resistant applications at temperatures below 30°F (°C).

Potential applications include the use of these materials as electrodes in certain high temperature electrolyzers and as reinforcing fibers in composite construction materials. The amorphous alloy, ie, metallic glass, of the present invention retains high thermal stability as revealed by differential thermal analysis (DTA) testing.

The temperature Tc for maximum crystallization is determined by whether excessive heat is generated at a special temperature (crystallization temperature) by gently heating the glass sample, or whether excessive heat is generated when the glass sample exceeds a special temperature range (glass transition temperature). It can be accurately determined from DTA by noting whether or not it is absorbed. Generally speaking, the less well-defined glass transition temperature is considered to be within about 50° below the lowest or first crystallization maximum point Tcl, and as is conventional, at temperatures above which the viscosity is about It covers a temperature range ranging from 1 and 3 to 1 and 4 poise. Metallic glasses are formed by cooling the melt at a rate of about 1°C/min.

A variety of methods are available, as known in the art, for making flat quenched foils, quenched ribbons, wires, etc. High Tg
Metallic glasses exhibiting I properties also exhibit high ductility and high corrosion resistance compared to highly crystalline or partially crystalline samples.

Moreover, these amorphous alloys have fairly high hardness values.
Metal-metal compositions Also in accordance with the present invention, metals that provide consistent glass-forming behavior as well as high thermal stability include Ta-Ni, Nb-Ni
and three-phase modified systems with W, Ti and/or Zr.

Here, a certain composition has the general formula RrNist or RrN
is, R is Ta, Nb and/or W and T is T
i and/or Zr. Such a composition is 650o
It has a crystallization temperature in the range of ~800 qo. The Ta-Ni binary metallic glass crystallizes in the range of 7600 to 7800C, which is about 1000C higher than that of the Nb-Ni metallic glass. If a part of Ta is substituted with W, Tc increases only slightly (approximately 15 to 20o0), and there is no appreciable change even if the W content is increased. On the other hand, partial addition of Ti or Zr tends to lower Tc. For binary systems of Tarnjs and NbrNis, r is approximately 35-65.
A glass metal is formed when s is in the remaining range of 35 to 65 atomic %.

Optimal properties are obtained in the Tarnis system when r is in the range of about 35 to 50 atom % and s is in the range of about 50 to 65 atom %. T
For the ternary system range of a35NisW-s to Ta45NiSW55-s, the range of glass formation with consistently high Tg and high hardness is shown in Figure 1, which is similar to Ta-
It is a ternary composition diagram of W-Ni.

The polygon labeled a-b-c-d-a encompasses the optimal glass forming area. Outside of this compositional region, either no substantial degree of amorphism is obtained or the beneficial properties are reduced to an unacceptable extent. In FIG. 1, s is in the range of about 35 to 45 atomic percent. Since Ti or Zr tend to lower Tc, such additions should not exceed about 15 atomic percent, and preferably should not exceed 10%, to maintain high Tg and high hardness.

Generally speaking, the hardness of the above system is about 800 to 112 marks P.
It is in the H range.

Examples Metals - Air arc for melting and liquid quenching of metal compositions high temperature reactive alloys -
A flat plate device was used.

This equipment is a secondary lightning arc melting button furnace modified to perform "hammer and anvil" flat plate quenching of alloys in an inert atmosphere, coupled to a 4-inch diffusion pump system. It includes the fuzen steel room. Quenching is accomplished by equipping the chamber with a planar water-cooled steel hearth on the floor and an air-driven copper ingot hammer positioned above the molten metal. Conventionally, arc melting is accomplished by negatively biasing a copper ball with a tungsten tip inserted through the top of the chamber and positively biasing the bottom of the chamber. P-containing alloys were made by homogenizing the powder components by condensation and then arc melting. All other alloys were made directly by repeated electric arc melting of the constituent elements. A single alloy button (approximately 200 c) was remelted and then "impact-quenched" into approximately 0.004 inch thick foil with a hammer placed directly above the molten pool. The cooling rate obtained with this method was about 1 to 1 degrees C./sec. The foil is X-ray diode and D
Amorphousity was tested on TA. The shock-quenched foil directly under the hammer may undergo plastic deformation after solidification.

However, some of the foil formed from the melt that protruded from the hammer was not deformed and was therefore passed for hardness and other related tests. The hardness was measured by the diamond pyramid method using a Pickers type indenter made of pyramidal diamond with a square bottom including an angle of 136° between opposing surfaces. Crystallization temperatures and hardness values for various metal-metal compositions are shown in Table 1. Table 1

[Brief explanation of the drawing]

FIG. 1 is a ternary composition diagram expressed in atomic percent of the metal-metal system Ta-W-Ni. Hoko figure

Claims (1)

[Claims] 1 Formula R_rNi_s (wherein R is at least one element selected from the group consisting of tantalum, niobium, and tungsten, and r
is 35 to 65 atom %, s is 5 to 65 atom %, and the sum of r and s is 100. ), and 650°C to 800°C
An amorphous metal alloy which is at least 50% amorphous and has a high crystallization temperature and a high hardness, characterized in that it has a crystallization temperature in the range of and a hardness in the range of 800-1125 DPH. 2 Formula R_rNi_sT_t (However, R is at least one element selected from the group consisting of tantalum, niobium, and tungsten, and T
is at least one element selected from the group consisting of titanium and zirconium, r is 35 to 65 atomic %, s is 25 to 65 atomic %, t is 15 atomic % or less, and r, s and The sum of t is 100. ), at least 50% amorphous and highly crystalline, characterized by having a crystallization temperature within the range of 650°C to 800°C and a hardness within the range of 800 to 1125 DPH Amorphous metal alloy with high temperature and hardness.